#define _CRT_SECURE_NO_WARNINGS


#include <stdio.h>
int main()
{
	int n = 0;
	int i = 1;
	int ret = 1;
	scanf("%d", &n);
	for (i = 1;i <= n;i++) {
		ret = ret * i;
	}
	printf("%d", ret);

	return 0;
};